UV Colour Photography Using IR Film

Besides using the "normal" tungsten-balanced Fuji RTP film, I have obtained some UV colour images by Kodak Infrared Ektachrome (EIR). These images are presented here and to the best of my knowledge it's the first time UV colour work is done with this film. The reasons why EIR is not optimal for UV colour use, however, is given here.

However, although EIR is slightly difficult to apply to UV colour photography in general, it's still possible to obtain quite nice UV pictures with it. Again, my favourite subject - the dandelion - is pressed into service. I used my UV-Nikkor 105 mm f/4.5 lens on an F5 camera to take the pictures shown below.

This image resulted when I used a Hoya U-360 filter over the lens and exposed the flower under a diffuse sun. U-360 is optically denser than Nikon's proprietary UV bandpass filter and thus transmits less readily in deep red. The drawback of this is that U-360 attenuates longwave UV to the extent that using it with ordinary lenses renders most objects highly contaminated with reds (look here for an explanation of this phenomenon). I didn't experience that problem here because the UV-Nikkor transmits more than 70% of the incident UV radiation. However, there is an anomaly of the colour rendition of the dandelion heads that I presently lack a verified explanation for. Note that the inner area of the flower head is rendered quite bright, in contrast with UV images on Fuji RTP. One reason for this could be an elevated IR reflectance within the same part of the flower to give a bright colour there.

(Click on thumbnail to get a full image)

For this shot, I added fill-in flash from my SB-140 UV flash unit, with a UV bandpass filter placed over the flash head. The central area of the flower head is rendered dark, to indicate the well-documented low UV reflectance there. Although the incident UV level is amplified by the UV flash output, there is noticeable less colour differention of the floral parts than that obtained with Fuji RTP and equivalent flash technique.

(Click on thumbnail to get a full image)

For this last image, I used Nikon's UV bandpass filter and a long-time exposure in subdued daylight. No additional flash was used. There is more colour differentation present within the flower itself, however, details are blurred by subject movement. Again, one obtains similar pictorial information as that given by Fuji RTP, the latter film however renders such scenes with enhanced colour clarity.

(Click on thumbnail to get a full image)

I intend to continue experimenting with the EIR film for this line of work. The much higher inherent UV sensitivity of EIR compared with RTP is a strong point in the case, but I'm not -yet- pleased with the colour rendition. After all, UV images should also be effective as a visual means of communicating.

UV images may also be acquired using digital techniques. For an updated review of digital UV and IR photography, click here.

Last Update 1 October, 2002